Magneto-thermal coupling simulation and experimental verification for a three-winding high-frequency transformer

Abstract

As a core component of the power electronic transformer (PET) in DC network, the multi-level high-frequency power transformer has received great attention due to the insulation material fatigue problems resulting from the hot-spot temperature rises. To solve this problem, a three-winding high-frequency transformer for 10 kVA PET application is designed and made in the laboratory, and the loss and temperature rise distribution is calculated by means of the finite element (FE) electromagnetic-thermal coupling simulation. The influence of temperature on the hysteresis and loss properties of core material has been carefully considered and measured. The influence of skin effect and end effect on the winding loss is taken into account through the establishing three-dimensional FE model. Besides, the convective heat transfer coefficient is solved based on the principle of heat transfer instead of the empirical coefficient method. By compared with the experimental results, the calculated results are validated to be effective in predicting the loss and hot-spot temperature rises of the transformer.

Keywords

Three-winding high-frequency transformer magneto-thermal coupling temperature effect two-way multiple iterations calculation loss calculation

Get full access to this article

View all access options for this article.

References

CIGRE B4-52 Working Group. HVDC Grid Feasibility Study, Melbourne, International Council on Large Electric Systems, 2011.

Khan

F.H.

, Hybrid electric vehicle power management solutions based on isolated and nonisolated configurations of multilevel modular capacitor-clamped converter, IEEE Trans Ind Electron 56 (2009), 3079–3095.

, System integration and hierarchical power management strategy for a solid-state transformer interfaced microgrid system, IEEE Trans Power Electron 29 (2014), 4414–4425.

Bahmani

M.A.

, Comparative study of a multi-MW high-power density DC transformer with an optimized high-frequency magnetics in all-DC offshore wind farm, IEEE Trans Power Deliv 31 (2016), 857–866.

Zhao

, High-frequency transformer design for modular power conversion from medium-voltage AC to 400 VDC, IEEE Trans Power Electron 33 (2018), 7545–7557.

Zhang

, Optimisation design of medium frequency transformer for the offshore DC grid based on multi-objective genetic algorithm, IET Power Electron 10 (2017), 2157–2162.

Leibl

M.G.

Ortiz

and Kolar

J.W.

, Design and experimental analysis of a medium-frequency transformer for solid-state transformer application, IEEE J Sel Topics Quantum Electron 5 (2017), 110–123.

Shen

, Design of High-density Transformers for High-frequency High-power Converters, PhD dissertation, Virginia, 2006.

Kauder

, Performance factor comparison of nanocrystalline, amorphous and crystalline soft-magnetic materials for medium-frequency applications, IEEE Trans Magn 53 (2017), 8401504.

10.

Gohil

, Optimized integrated harmonic filter inductor for dual-converter-fed open-end transformer topology, IEEE Trans Power Electron 32 (2017), 1818–1831.

11.

Steinmetz

C.P.

, On the law of hysteresis, AIEE Trans 9 (1892), 3–64.

12.

Bertotti

, General properties of power losses in soft ferromagnetic materials, IEEE Trans Magn 24 (1988), 621–630.

13.

Rongzhen

H.E.

, Research on Core Loss Performance of High Frequency Transformer under PWM Excitation, Shenyang University of Technology, Shenyang, China, 2019.

14.

Dowell

, Effects of eddy currents in transformer windings, Proceedings of the Institution of Electrical Engineers 113 (1966), 1387–1394.

15.

Ferreira

J.A.

, Experimental evaluation of losses in magnetic components for power converters, IEEE Trans Ind Appl 27 (1991), 335–339.

16.

Bahmani

M.A.

, An accurate pseudo empirical model of winding loss calculation in HF foil and round conductors in switch mode magnetics, IEEE Trans Power Electron 29 (2014), 4231–4246.

17.

Bin

, Design optimisation of an inductor-integrated MF transformer for a high-power isolated dual-active-bridge DC–DC converter, IET Power Electron 12 (2019), 2912–2922.

18.

Bahmani

M.A.

, Design methodology and optimization of a medium frequency transformer for high power DC–DC Appl, IEEE Trans Ind Appl 52 (2016), 4225–4233.

19.

Mogorovic

, Sensitivity analysis of medium-frequency transformer designs for solid-state transformers, IEEE Trans Power Electron 34 (2019), 8356–8367.

20.

Shafaei

, Three-dimensional frequency-dependent thermal model for planar transformers in LLC resonant converters, IEEE Trans Power Electron 34 (2019), 4641–4655.

21.

Djamali

, Malfunction detection of the cooling system in air-forced power transformers using online thermal monitoring, IEEE Trans Power Deliv 32 (2017), 1058–1067.

22.

Wang

, Analysis of power loss and temperature rise characteristic of high frequency transformer, PhD dissertation, Hebei University of Technology, China, 2014.

23.

Jiewei

, Transient simulation analysis of electromagnetic field and temperature field of high-frequency transformer, High Voltage Engineering 45 (2019), 1191–120.

24.

Liao

, 3-D coupled electromagnetic-fluid-thermal analysis of oil-immersed triangular wound core transformer, IEEE Trans Magn 50 (2014), 1–4.

25.

VDI. VDI Heat Atlas, 6th ed. Springer, 2012.

26.

Dutta

, A digital predictive current-mode controller for a single-phase high-frequency transformer-isolated dual-active bridge DC-to-DC converter, IEEE Trans Ind Electron 63 (2016), 5943–5952.

27.

Appino

Ferrara

Fiorillo

Rocchino

Ragusa

Sievert

, International comparison on SST and epstein measurements in grain-oriented Fe–Si sheet steel, International Journal of Applied Electromagnetics and Mechanics 48 (2015), 123–133.